A device for the metered delivery of a viscous liquid is known from the Singapore patent application SG 0074739. This device comprises a pump body with a drill hole which connects an intake chamber and a discharge chamber. In this drill hole, two pistons are moved back and forth between the intake chamber and the discharge chamber. A slot of variable width is formed between the faces of the two pistons so that the liquid in the intake chamber fills the slot and is pressed out of the slot into the discharge chamber. To guide the pistons, guide rails are present which are guided in further, parallel running drill holes.
This device has two disadvantages. When used for applying adhesive, it can happen that flakes of silver contained in the adhesive make their way to the outside of the pump body and from there into the drill holes which accommodate the guide rails which leads to the guide rails sticking. Furthermore, the friction of the guide rails in the drill holes is too great.
The object of the invention is to rectify the above mentioned shortcomings.